The present invention relates to a foil bag of the type provided with tearing means which serve as an opening aid, and a method for its manufacture.
Such opening aids are known. For example, U.S. Pat. No. 2,353,746 describes a foil bag having a flattened head portion in which a tear string is embedded. The string extends along the inside of the bag and is disposed within the head portion next to a transverse seam. One end of the string is brought to the outside through this transverse seam. To open the bag, the bag must first be torn transversely to the transverse seam and then alongside the seam. If the procedure followed is different in any respect, the bag may be impossible to open under certain circumstances.
German Offenlegungsschrift [Laid-open Application] No. 2,813,598 discloses an opening aid of the above-mentioned type in which one wall of the bag is provided with two openings in the form of straight cuts which are spaced from the respective lateral limits of the head portion and through which the tearing means is inserted and thus forms two gripping pieces. The contacting walls of the head portion are sealed around the cuts. Thus the inserted band undergoes an abrupt change in direction at the cuts. In the region of these cuts, the wrapping material forms waves and folds so that a gas-tight seal can be attained only with difficulty.
Swiss Pat. No. 595,983 describes a foil bag with a tear strip whose gripping end is made accessible in that the wrapping material is provided with a U-shaped cut around the gripping end. The arms of the cut are bent over when the longitudinal edges of the head portion are formed so that the gripping end and the cut-out flap spread open upon folding and project beyond the edge. This requires a selection from a limited number of available materials, so that such bags can be manufactured only for limited use.